This invention relates generally to the field of heat pipes, and more particularly to heat pipes suitable for use under conditions of variable and high peak heat loads caused by the use of pulsed high energy sources or other similar equipment.
Heat pipes use successive evaporation and condensation of a working fluid to take advantage of the high heat of vaporization found in most fluids to transfer large amounts of thermal energy over relatively small temperature gradients.
The primary use of heat pipes is in cooling, where the heat pipe is used to transfer thermal energy from a heat source to a heat sink. Such heat pipes are typically of two basic types, selected according to the nature of the heat source from which heat is to be removed. The steady state heat pipe is the simplest and is designed to remove thermal energy from a heat source of relatively constant output. The variable conductance heat pipe is more complicated and is designed to remove thermal energy from a heat source that varies in thermal energy output. In normal use, the thermal conductance of the variable conductance heat pipe is varied to maintain a constant temperature of the heat source.
Variable conductance heat pipes are designed to operate efficiently only over a specific and limited range of thermal energy transfer. They are not suitable for use where the peak thermal energy output load is very much greater than the normal load. This can occur when operating high energy pulsed devices which will dissipate extremely high levels of thermal energy, but only for short periods, yet still require the heat pipe to efficiently remove thermal energy during other phases of operation of the devices which produce a lower thermal energy output.
With the foregoing in mind, it is, therefore, a principal object of the present invention to provide a heat pipe design able to efficiently remove thermal energy during periods of pulsed high thermal energy output, as well as during periods of lower thermal energy output.
It is a further object of the present invention to provide a heat pipe design that allows rapid start-up of the heat pipe.